I think Trackman Goggles have a thing for that.
Wait, looking at the Code I think I know what happened. So the Pipes were as I expected not supposed to ever dump Items on the Floor at all.
Now Railcrafts Air Block comes into play, because that one has a TileEntity, which in turn makes the target check pass. This means the Pipe will use the Item Movement Utility to move Items into that location. But that Utility actually knows that it’s an Air Block and dumps it anyways.